WO2002083761A1 - Use of zinc derivatives as cyclic ester polymerisation catalysts - Google Patents

Abstract

The invention concerns the use of zinc derivatives of general formula (I) wherein: L1 represents a group of formula: -E14(R14)(R'14)(R''14), -E15(R15)(R'15) or -E16(R16); E is an atom of group 15; L2 and L3 independently represent a group of formula: -E14(R14)(R'14)(R''14), -E15(R15)(R'15) or -E16(R16), or together form a chain of formula -L'2-A-L'3-; A represents a saturated or unsaturated chain comprising one, two or three elements of group 14; L'2 and L'3 independently represent a group of formula -E14(R14)(R'14) -E15(R15) or -E16-; E14 is an element of group 14; E15 is an element of group 15; E16 is an element of group 16; R14, R'14, R''14, R15, R'15 and R16 represent various groups, as (co) polymerisation catalysts of cyclic esters.

Description

 Use of zinc derivatives as catalysts for polymerization of cyclic esters

Over the past twenty years, biodegradable polymers have experienced considerable growth. In particular, polyesters such as poly-ε-caprolactones, polylactides and polyglycolides are well suited for many industrial applications (packaging, household products, etc.), pharmaceuticals (controlled and prolonged release systems) and medical (sutures, prostheses, etc.). They are generally prepared by ring opening polymerization using metal derivatives, in particular aluminum, tin and zinc (Kuran Prog. Polym. Sci. 1998, 23, 919). These polymerizations are most often carried out in a heterogeneous medium and lead to fairly wide mass distributions.

Among all the polyesters, the copolymers appear as "tailor-made" macromolecules. Depending on the desired applications, their properties can indeed be adjusted by varying different parameters (chain length and mass distribution, but also the nature, proportion and chain of monomers and also the nature of the chain ends). There is therefore a need for new homogeneous phase polymerization processes allowing the control of all these parameters.

In this area, work in recent years has mainly focused on new more or less sophisticated catalytic systems such as porphyrin ligand systems [Inoue Ace Chem Res (1996) 29, 39], diamido-amine [Bertrand J Am Chem Soc (1996) 118, 5822; Organometalhcs (1998) 17, 3599] or β-diiminate [Coates J Am Chem Soc (1999) 121, 11583; Polym. Prep. (1999) 40, 542].

The present invention provides a process for (co) polymerization of cyclic esters that is both simple and effective, having many advantages, in particular: - the (co) polymerization catalysts used, based on zinc, are easily accessible and good market ; they are little or not toxic. These are well defined compounds (they exist in the form of monomer and / or dimer); - The (co) polymerization can be truly carried out in a homogeneous medium so that the mass distribution of the (co) polymers obtained is narrow; such a process is very suitable for the preparation of block copolymers.

The successive addition of monomers makes it possible in particular to obtain block copolymers. Finally, the process makes it possible to completely control the nature of the ends of the (co) polymers. The present invention therefore relates to the use of zinc derivatives of general formula (1)

in which Li represents a group of formula -Ei ₄ (R ₁₄ ) (R _'14 ) (R "ι ₄ ), -Ei ₅ (Rι ₅ ) (R'ι ₅ ) or

-E ₁₆ (Rι ₆ );

E is a group 15 atom;

L ₂ and L ₃ independently represent a group of formula

-Ei ₄ (R ₁₄ ) (R _'14 ) (R "i ₄ ), -E ₁₅ (Rι ₅ ) (R'ι ₅ ) or -Eι ₆ (R ₁₆ ), or together form a chain of formula -L ^ -AL ^ -;

A represents a saturated or unsaturated chain comprising one, two or three elements of group 14, each being optionally and independently substituted by one of the following substituted (by one or more identical or different substituents) or unsubstituted radicals: alkyl, cycloalkyl , aryl, wherein said substituent is a halogen atom, the alkyl, aryl, nitro or cyano radical;

L ' ₂ and L' ₃ independently represent a group of formula -Eι ₄ (R ₁₄ ) (R _'14 ) -, -E ₁₅ (R ₁₅ ) - or -E ₁₆ -; E ₁₄ is an element of group 14 E ₁₅ is an element of group 15

E ₁₆ is an element of group 16 R ₁₄ , R _'14 , R'Η, R ₁₅ , R' ₁₅ and Rι ₆ represent, independently, the hydrogen atom; one of the following substituted (by one or more identical or different substituents) or unsubstituted radicals: alkyl, cycloalkyl or aryl, in which said substituent is a halogen atom, the alkyl, cycloalkyl, aryl, nitro or cyano radical ; a radical of formula -E _'14 RRR ";E' ₁₄ is an element of group 14;

R, R 'and R "independently represent the hydrogen atom or one of the following substituted (by one or more identical or different substituents) or unsubstituted radicals: alkyl, cycloalkyl, aryl, in which said substituent is a halogen atom, the alkyl, aryl, nitro or cyano radical; as catalysts for (co) polymerization of cyclic esters.

In the definitions indicated above, the expression halogen represents a fluorine, chlorine, bromine or iodine atom, preferably chlorine. The expression alkyl preferably represents an alkyl radical having from 1 to 6 linear carbon atoms n - J - or branched and in particular an alkyl radical having from 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl radicals.

The cycloalkyl radicals are chosen from saturated or unsaturated monocyclic cycloalkyls. The saturated monocyclic cycloalkyl radicals can be chosen from radicals having from 3 to 7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl radicals. The unsaturated cycloalkyl radicals can be chosen from cyclobutene, cyclopentene, cyclohexene, cyclopentadiene, cyclohexadiene radicals.

The aryl radicals can be of the mono or polycyclic type. The monocyclic aryl radicals can be chosen from phenyl radicals optionally substituted by one or more alkyl radicals such as tolyl, xylyl, mesityl, cumenyl. The polycyclic aryl radicals can be chosen from the naphthyl, anthryl and phenanthryl radicals.

The compounds of formula (1) can be in the form of a monomer and / or a cyclic dimer:

The compounds of formula (1) may contain one or more solvent molecules [complexes of zinc with one or two molecules of tetrahydrofuran have been isolated and fully characterized: KG Caulton et al., Inorg. Chem. (1986) 25, 1803; DJ Darensbourg et al., J. Am. Chem. Soc. (1999) 121, 107] or alternatively one or more phosphines [complexes of zinc with one or two phosphine molecules have been isolated and fully characterized: DJ Darensbourg et al., Inorg. Chem. (1998) 37, 2852 and ibid (2000) 39, 1578]. The expression solvent represents an aromatic hydrocarbon such as benzene, toluene; a cyclic or acyclic ether dialkyl such as diethyl ether, dioxane, tetrahydrofuran, ethyl tert-butyl ether; a chlorinated solvent such as dichloromethane, chloroform; an aliphatic or aromatic nitrile such as acetonitrile, benzonitrile; an aliphatic or aromatic, cyclic or acyclic ketone such as acetone, acetophenone, cyclohexanone; an aliphatic or aromatic, cyclic or acyclic carboxylic acid derivative such as ethyl acetate, dimethylformamide. The expression phosphine represents an aromatic and / or aliphatic tertiary phosphine such as triphenylphosphine, diphenylmethylphosphine, dimethylphenylphosphine, tributylphosphine, trimethylphosphine.

A more particular subject of the invention is the use, as catalysts of (co) polymerization of cyclic esters, of compounds of general formula (1) as defined above, characterized in that

E is a nitrogen or phosphorus atom;

Ei ₄ is a carbon or silicon atom;

E ₁₅ is a nitrogen or phosphorus atom; Ei ₆ is an oxygen or sulfur atom;

A represents a saturated or unsaturated chain comprising one, two or three elements of group 14, each being optionally and independently substituted by an alkyl or aryl radical; i4 "R'i4 _> R" i _4> I5J R'i5 ^and Ri6 independently represent the hydrogen atom, an alkyl radical, an aryl radical or a radical of formula

-E 'ι ₄ RR'R ";

E 'H is a carbon or silicon atom;

R, R 'and R "independently represent the hydrogen atom or an alkyl radical,

and preferably,

E is a nitrogen atom;

E ₁₄ is a carbon atom;

Ei ₅ is a nitrogen atom;

Ei ₆ is an oxygen or sulfur atom; R ₁₄ , R _'14 , R'Η, Ri ₅ and R' ₁₅ independently represent an alkyl radical or of formula -E'ι ₄ RR'R ";

RI ₆ represents an alkyl or aryl radical optionally substituted by one or more substituents chosen from alkyl and halogen radicals;

E _'14 represents a silicon atom; R, R 'and R "independently represent the hydrogen atom or a methyl, ethyl, propyl or isopropyl radical.

The invention more particularly also relates to the use, as catalysts of (co) polymerization of cyclic esters, compounds of general formula (1) as defined above, characterized in that Lι represents a group of formula -Ei ₅ (Ri ₅ ) (R'i ₅ ); L ₂ and L ₃ independently represent a group of formula

-E ₁ 4 (Rι ₄ ) (R'i4) (R "i4); and preferably

E is a nitrogen atom; Ej ₅ is a nitrogen atom;

Ri ₄ , R _'14 , R'Η, R ₁₅ and R' ₁₅ independently represent an alkyl radical or of formula -E'uRR'R ";

R, R 'and R "independently represent an optionally substituted alkyl radical.

Very preferably, the compound of formula (1) as defined above, corresponds to the following formula: [(Me ₃ Si) ₂ N] ₂ Zn.

Some of the compounds of formula (1) are known products, that is to say the synthesis and characterization of which have been described [H. Bϋrger, W. Sawodny, U. Wannagat, J. Organometal. Chem. (1965) 3, 113; K. Hedberg et al., Inorg Chem. (1984) 23, 1972; P. P. Power et al., Inorg. Chem. (1991) 30, 5013; H. Schumann et al., Z. Anorg. Allg. Chem. (1997) 623, 1881 and ibid. (2000) 626, 747]. Consequently, the new compounds of formula (1) can be prepared by analogy with the synthetic routes already described.

The invention relates to the use of the products of formula (1) as defined above, as catalysts for the implementation of (co) polymerization of cyclic esters, that is to say of polymerization or copolymerization of 'cyclic esters. During the implementation of these (co) polymerizations, the compounds according to the invention play the role of initiator and / or chain regulator.

Cyclic esters can have a size ranging from four to eight links. By way of example of cyclic esters corresponding to the above formulation, mention may be made of ε-caprolactone and the polymeric cyclic esters of lactic and / or glycolic acid. Random or block copolymers can be obtained depending on whether the monomers are introduced together at the start of the reaction, or sequentially during the reaction.

The subject of the invention is also a process for the preparation of polymers or copolymers, block or random, which consists in bringing together one or more monomers, a chain initiator, a polymerization catalyst, and optionally an additive, said process characterized in that the chain initiator and the polymerization catalyst are represented by the same compound which is chosen from the compounds of formula (1) as defined above. The term additive represents any protic reagent such as water, hydrogen sulfide, ammonia, an aliphatic or aromatic alcohol, an aliphatic or aromatic thiol, a primary or secondary amine, aliphatic or aromatic, cyclic or acyclic. This reagent is capable of exchanging one of the substituents of the product of formula (1), which makes it possible to control the nature of one of the chain ends.

The (co) polymerization can be carried out either in solution or by supercooling. When the (co) polymerization is carried out in solution, the reaction solvent can be the (or one of the) substrate (s) used in the catalytic reaction. Solvents which do not interfere with the catalytic reaction itself are also suitable. By way of example of such solvents, mention may be made of saturated or aromatic hydrocarbons, ethers, aliphatic or aromatic halides.

The reactions are carried out at temperatures between room temperature and about 250 ° C; the temperature range between 20 and 180 ° C is more advantageous. The reaction times are between a few minutes and 300 hours, and preferably between 5 minutes and 72 hours.

This (co) polymerization process is particularly suitable for obtaining (co) polymers of cyclic esters, in particular the cyclic esters polymer of lactic and / or glycolic acid. The products obtained such as glycolic lactic copolymers are biodegradable, and are advantageously used as a support in therapeutic compositions with sustained release.

Finally, the invention relates to polymers or copolymers capable of being obtained by the implementation of a process as described above.

Unless they are defined in another way, all the technical and scientific terms used in the present application have the same meaning as that commonly understood by an ordinary specialist in the field to which the invention belongs. Likewise, all publications, patent applications and all other references mentioned in this application are incorporated by reference.

The following examples are presented to illustrate the above procedures and should in no way be taken as limiting the scope of the invention.

Example 1: Preparation of an oligomer with controlled chain ends (amido-alcohol) H ₂ N- (D, L-lactide) _n -H 0.2 g (0.52 mmol) of [(Me ₃ Si) ₂ N] ₂ Zn and 10 ml of dichloromethane are successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon. To the above solution are added 0.6 g (4.16 mmol) of D, L-lactide dissolved in 30 ml of dichloromethane. The reaction mixture is left under stirring at 40 ° C for 20 hours. Analysis of an aliquot by proton NMR shows that the conversion of D, L-lactide is greater than 95%. To the preceding solution are added 0.5 ml of methanol and stirring is continued for 10 min. Evaporation of the solvent followed by extraction with acetonitrile makes it possible to isolate the oligomer in the form of a white solid. The nature of the chain ends of this oligomer is determined by mass spectrometry (ionization by electrospray, detection in positive ion mode, sample dissolved in acetonitrile with a trace of ammonium hydroxide).

Example 2: Preparation of an oligomer with controlled chain ends (ester-alcohol) -PrO- (D, L-lactide) „- H

0.2 g (0.52 mmol) of [(Me ₃ Si) ₂ N] ₂ Zn, 40 μl (0.52 mmol) is successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon isopropanol and 10 ml of dichloromethane. The reaction mixture is left under stirring at room temperature for 10 minutes. After adding 0.6 g (4.16 mmol) of D, L-lactide in solution in 20 ml of dichloromethane, the reaction medium is left under stirring at room temperature for 60 hours. Analysis of an aliquot by proton NMR shows that the conversion of D, L-lactide is greater than 95%. To the preceding solution are added 0.5 ml of methanol and stirring is continued for 10 min. Evaporation of the solvent followed by extraction with acetonitrile makes it possible to isolate the oligomer in the form of a white paste. The nature of the chain ends of this oligomer is determined by proton NMR and by mass spectrometry (ionization by electrospray, detection in positive ion mode, sample dissolved in acetonitrile with a trace of ammonium hydroxide).

Example 3: Preparation of an oligomer with controlled chain ends (ester-anhydride) * ^' -PrO- (D, L-lactide) „- COCH ₃

0.2 g (0.52 mmol) of [(Me ₃ Si) ₂ N] ₂ Zn, 40 μil (0.52 mmol) is successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon isopropanol and 10 ml of dichloromethane. The reaction mixture is left under stirring at room temperature for 10 minutes. After adding 0.6 g (4.16 mmol) of D, L-lactide in solution in 20 ml of dichloromethane, the reaction medium is left under stirring at room temperature for 24 hours. Analysis of an aliquot by proton NMR shows that the conversion of D, L-lactide is greater than 95%. To the above solution are added 0.2 ml of acetic anhydride and stirring is continued for 10 min. Evaporation of the solvent followed by extraction with acetonitrile makes it possible to isolate the oligomer in the form of a white paste. The nature of the chain ends of this oligomer is determined by proton NMR and by mass spectrometry (ionization by electrospray, detection in positive ion mode, sample dissolved in acetonitrile with a trace of ammonium hydroxide).

Example 4 Preparation of a random copolymer (D, L-lactide / glycolide) of mass 15,000 having a lactide / glycolide composition close to 50/50

3.92 g (27.3 mmol) of D, L-lactide, 3.11 g (27.3 mmol) of glycolide are successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon. 12 ml of mesitylene then, at 180 ° C, a solution of 0.07 g (0.18 mmol) of [(Me ₃ Si) 2N] ₂ Zn in 1 ml of mesitylene. The reaction mixture is left under stirring at 180 ° C for 2 hours. A proton NMR analysis makes it possible to verify that the conversion is 94% for the lactide and 100% for the glycolide. The ratio of the signal integrals corresponding to the polylactide (5.20 ppm) and polyglycolide (4.85 ppm) part makes it possible to evaluate the composition of the copolymer at 50% lactide and 50% glycolide. According to a GPC analysis, using a calibration carried out using PS standards of masses 761 to 400,000, this copolymer is a mixture of macromolecules (Mw / Mn = 1.98) of low masses (Mw = 15,000 Dalton).

Example 5 Preparation of a random copolymer (D, L-lactide / glycolide) of mass 35,000 having a lactide / glycolide composition close to 50/50

7.84 g (54.6 mmol) of D, L-lactide, 6.22 g (54.6 mmol) of glycolide and 12 are successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon. ml of mesitylene then, at 180 ° C, a solution of 0.07 g (0.18 mmol) of [(Me3Si) ₂ N] 2Zn in 1 ml of mesitylene. The reaction mixture is left under stirring at 180 ° C for 2 hours. Proton NMR analysis allows verify that the conversion is 78% for lactide and 100% for glycolide. The ratio of the signal integrals corresponding to the polylactide (5.20 ppm) and polyglycolide (4.85 ppm) part makes it possible to evaluate the composition of the copolymer at 47% lactide and 53% glycolide. According to an analysis by GPC, using a calibration made from PS standards of masses 761 to 400,000, this copolymer is a mixture of macromolecules (Mw / Mn = 1.56) of fairly high masses (Mw = 35,000 Dalton).

Example 6 Preparation of a random copolymer (D, L-lactide / glycolide) with a mass of 45,000 having a lactide / glycolide composition close to 50/50

3.92 g (27.2 mmol) of D, L-lactide, 3.11 g (27.2 mmol) of glycolide and 13 are successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon. ml of mesitylene. Then, at 180 ° C., a solution of 70 mg (0.18 mmol) of

and 14 μl (0.18 mmol) of isopropanol in 2 ml of mesitylene. The reaction mixture is left under stirring at 180 ° C for 2 hours. A proton NMR analysis makes it possible to verify that the conversion is 80% for the lactide and 100% for the glycolide. The ratio of the signal integrals corresponding to the polylactide (5.20 ppm) and polyglycolide (4.85 ppm) part makes it possible to evaluate the composition of the copolymer at 44% lactide and 56% glycolide. According to an analysis by GPC, using a calibration made from PS standards of masses 761 to 400,000, this copolymer is a mixture of macromolecules (Mw / Mn = 1.65) of fairly high masses (Mw = 45,000 Dalton).

Example 7: Preparation of a block (D, L-lactide / glycolide) copolymer

4.7 g (33.5 mmol) of D, L-lactide and 15 ml of mesitylene are successively introduced into a Schlenk tube fitted with a magnetic bar purged under argon. Then at

180 ° C., a solution of 86 mg (0.22 mmol) of [(Me ₃ Si) 2N] ₂ Zn and 17 μl (0.22 mmol) of isopropanol in 3 ml of mesitylene are added. The reaction mixture is left under stirring at 180 ° C for 2 hours. A proton NMR analysis makes it possible to verify that the conversion of the monomer is complete. To the above solution kept under stirring at 180 ° C. are added 0.5 g (4.5 mmol) of glycolide. The reaction mixture is left under stirring at 180 ° C for 1 hour. Analysis of an aliquot by proton NMR shows that the conversion of lactide and glycolide is complete and that a copolymer is formed. The ratio of the signal integrals corresponding to the polylactide (5.20 ppm) and polyglycolide (4.85 ppm) part is 9/1. GPC analysis indicates that this copolymer is a mixture of macromolecules with a low polydispersity index (Mw = 20,400 Dalton, Mw / Mn = 1.441).

Claims

1. Use of zinc derivatives of general formula (1)

in which Li represents a group of formula -Ei ₄ (R ₁ ) (R _'14 ) (R "i ₄ ),

or

-Eι ₆ (Rι ₆ );

E is a group 15 atom;

L ₂ and L ₃ independently represent a group of formula

-E] ₄ (Ri ₄ ) (R'i ₄ ) (R "i ₄ ), -Eι ₅ (Rι ₅ ) (R _'15 ) or -Eι ₆ (Ri ₆ ), or together form a chain of formula - L ' ₂ -A-L' ₃ -;

A represents a saturated or unsaturated chain comprising one, two or three elements of group 14, each one being optionally and independently substituted by one of the following substituted or unsubstituted radicals: alkyl, cycloalkyl, aryl, in which said substituent is an atom halogen, the alkyl, aryl, nitro or cyano radical;

L ' ₂ and L' ₃ independently represent a group of formula -E ₁₄ (Ri4) (R'i4) -, -Eι ₅ (Rι ₅ ) - or -Eι ₆ -; E ₁₄ is an element of group 14; Ei ₅ is an element of group 15; Ei ₅ is an element of group 16;

R ₁₄ , R _'14 , R "H, R ₁₅ , R' ₁₅ and Rι ₆ represent, independently, the hydrogen atom; one of the following substituted or unsubstituted radicals: alkyl, cycloalkyl or aryl, in which said substituent is a halogen atom, the alkyl, cycloalkyl, aryl, nitro or cyano radical; a radical of formula -E'ι ₄ RR'R ";

E _'14 is an element of group 14;

R, R 'and R "independently represent the hydrogen atom or one of the following substituted (by one or more identical or different substituents) or unsubstituted radicals: alkyl, cycloalkyl, aryl, in which said substituent is a halogen atom, the alkyl, aryl, nitro or cyano radical; as catalysts for (co) polymerization of cyclic esters.

2. Use, according to claim 1, of a compound of formula (1) characterized in that

E is a nitrogen or phosphorus atom;

E ₁ 4 is a carbon or silicon atom; Ei ₅ is a nitrogen or phosphorus atom;

E ₁₅ is an oxygen or sulfur atom;

A represents a saturated or unsaturated chain comprising one, two or three elements of group 14, each being optionally and independently substituted by an alkyl or aryl radical; R ₁₄ , R'u, R'Η, R ₁₅ , R'is and Rι ₆ represent, independently, the hydrogen atom, an alkyl radical, an aryl radical or a radical of formula

-E'uRR'R ";

E _'14 is a carbon or silicon atom;

R, R and R "independently represent the hydrogen atom or an alkyl radical.

3. Use, according to claim 2, of a compound of formula (1) characterized in that

E is a nitrogen atom; E ₁₄ is a carbon atom; Ei ₅ is a nitrogen atom;

Ei ₆ is an oxygen or sulfur atom;

Ri ₄ , R'14, R "H _> Ri ₅ R'i5 independently represent an alkyl radical or of formula -E'ι ₄ RR'R";

Ri ₆ represents an alkyl or aryl radical optionally substituted by one or more substituents chosen from alkyl and halogen radicals;

E'i ₄ represents a silicon atom;

R, R 'and R "independently represent the hydrogen atom or a methyl, ethyl, propyl or isopropyl radical.

4. Use, according to claim 1, of a compound of formula (1) characterized in that

Li represents a group of formula -Ei ₅ (Ri ₅ ) (R'i ₅ );

L ₂ and L ₃ independently represent a group of formula

-Eι ₄ (Ri4) (R'i4) (R "i4);

5. Use, according to claim 4, of a compound of formula (1) characterized in that

E is a nitrogen atom: E ₁₅ is a nitrogen atom;

Ri ₄ , R _'14 , R'Η, Ri ₅ and R' ₁₅ independently represent an alkyl radical or of formula -E 'HRR'R ";

R, R 'and R "independently represent an optionally substituted alkyl radical.

6. Use, according to one of claims 2 to 5, of the compound of formula (1) characterized in that it corresponds to the formula [(Me3Si) 2N] 2Zn.

7. Use according to one of claims 1 to 6, for the polymerization or copolymerization of cyclic esters, in particular the polymeric cyclic esters of lactic and / or glycolic acid.

8. A process for preparing copolymers, block or random, or polymers, which consists in bringing one or more monomers, a polymerization catalyst and, optionally, an additive or even a polymerization solvent, at a temperature between ambient temperature and 250 ° C., for a period of between a few minutes and 300 hours, said process characterized in that the chain initiator and the polymerization catalyst are represented by the same compound of general formula (1) as defined in one of claims 1 to 6.

9. Method according to claim 8, characterized in that the monomer is chosen from cyclic esters, and in particular polymeric cyclic esters of lactic and / or glycolic acid.

10. Polymers or copolymers capable of being obtained by the implementation of a process according to one of claims 8 or 9.